Bolt-anchor.



H. vv. PLEISTER.

BOLT ANCHOR.

APPLICM'JON FILED APR. .7. 1917.

Patented Nov. 27, 191?.

15252.? 17j/@gig g/ ITE@ @ATEF PATENT HENRY W2 ELEISTER., 0F WESTFELID. NEW J fiSSGfNCll't TO HINMY E. 0E WESTFIZELD, NEW JERSEY.

@OLT-ANCHOR'.

Specification of Letters latent.

Original application filed January 20, 1917, Serial NO- 143,423. Divided and this application flied. April '7, 191'?v Serial No. 160,416.

relates to that class of bolt anchors known as anchors, lead anchors and Lscrew anchers, in which the material of the anchor is formed of more or less ductile material such as an alloy of lead, in which a wood screw will cut its own cooperating female threads. Such anchors are used to hold lighter work than are lag shields.

In the present form of anchors the maXimum expansion is approximately at the ex treme. inner end of the anchor. In practice this is often a serious detriment in that the wood screw having Jforced the anchor out to its maximum expansion binds and it is impossible to bring the head of the wood screw up flush with the work. rThis requires the hole to be enlarged entailing additional labor and expense, or a different size anchor has to be used.

Bv my invention I overcome this serious objection and give a longer surface of maximum contact or grip on the exterior of the anchor, thereby giving an increased frictional hold, and distributing this maximum grip over a larger area than with the pres- 4:0 ent form of anchors. My invention further permits the woodscrew to coperate with .the anchor with less eiiort than with the present forms.

In my present invention I provide the interior of the anchor with longitudinally cxtending ribs or surfaces which first engage and guide the screw as it is screwed home. The wood screw cuts its own cooperating screwthreads in these ribs or surfaces, and

generally, though not necessarily, cuts entirely through the ribs into the body oi' the anchor.

In my present invention I provide the anchor with a body formed with an axial bore inclined from near one end to a point intermediate the ends of the anchor, and from that point merging into a cylindrical bore, the inclined and cylindrical bores being provided with internal ribs of substantially the same height.

My invention further relates to certain details of construction which will be described in the specification and pointed out in the claims.

In the drawings the same reference numerals refer to similar parts in the dierent figures.

Figure 1 is a longitudinal, vertical section of my present invention;

Fig. 2 is a vertical section of the bolt anchor shown in Fig. 1, located within a wall or other support and cooperating with a wood screw;

Fig. 3 is a plan view ot the anchor shown in Fig. 1;

Fig. 4 is a transverse vertical section, substantially on the line '.l-ll et Fig. 1, lookingd in the direction of the arrows;

Fig. 5 is a transverse, vertical section,sub stantially on the line 5*.5 of Fig. 1, looking in the direction of the arrows; and

Fig. 6 is a vertical section of a modication in which the ribs are provided only upon the interior inclined bore of the anchor.

In the illustrative embodiment of my invention, 1. Fig. 1` is an anchor having a collar 2 and tines 3 and 4i. rIhis anchor has a body portion 5 provided with an inclined or conical axial bore 6 extending from substantially one end 7 to a point 8, which is the nearest approach to the axis of the anchor and which is located between the end 7 and the end 9. From the point S the axial 1oore is cylindrical to the end 9 of the anchor. 0f course the particular location otE the point 8 may he varied. @n the inclined or conical axial bor@ 6 and the cylindrical here 10, I term longitudinally extending` ribs 11 of substantially the same height throughout their length.

In my present invention, the point 8, where the ribs 11, 11 approach the nearest to the axis, is due to the 'formation oi2 the body portion 5 rather than to Varying the height or depth of the ribs 11, which is one of the forms shown in my said parent application. These ribs 11 serve to guide the en tering wood screw 12 and permit its easy passage into the anchor, its male threads 13 cutting their own coperating female threads in the ribs 11, and usually, though not nec# essarily, in the body 5 of the anchor also.

It is of course to be understood, that the depth of the screw threads cut by the screw depend upon the relative size of the anchor, the screw, the size of the hole and of the work or load 14. When this anchor is placed in the hole 15 of the support 16 its tines 3 and L1, will be expanded, the maximum grip of tl@ anchor in the hole of the support 16 will extend substantially from the points 17, 17 to the points 18, 18, thus giving a long surface of contact and increased frictional hold and distributing the maximum grip over a larger area than the old form of lead anchor now on the market. 'Ihese old forms employ a uniformly taperingaxial bore in which the maximum grip is at the extreme inner end of the anchor equivalent to thepoints 18, 18.

Not only is it easier to position the wood screw 12 and to obtain a stronger and more 'lasting grip upon the wall of the hole 15,

but when the support 16 happens to be material which may be damaged, as for example a thin slab of marble or plaster, or any other material, the maximum grip is distributed over a larger area to prevent any damage to the support.

In Fig. 2 I have shown the work 14- of a -cannot be brought up snugly against the work.

In Fig. 6 I have shown a bolt anchor 26 provided with an inclined axial bore 27 l reaching its nearest approach to the axis at 28 and there merging into a cylindrical bore 29. On the inclined axial bore I mount ribs 30, 80, which terminate at the point 28 and there merge into the unribbed or plain cylindrical bore 29.

That the screw does not jam is due to the fact that the point of maximum expansion is extended over a relatively large surface of the anchor, so that the end 22 of the screw 12 can be brought anywhere along that portion 23, 23 ofthe ribs 11, 11, which run parallel to each other,'or past the end of the anchor as may be found necessary to bring the head 21 flush against the work and at the same time obtain the requisite maximum expansion of the anchor. In the old form, where the maximum expansion is atthe end Lafrance of theanehor, at points equivalent .to the points 18, 18, the screw would often )am at this point before its head could be brought Hush with the work 19, whatever its thickness may be, requiring the removal of the anchor and the enlargement of the hole, or the use of a different size anchor.

My anchor may be formed of any exterior configuration. I have shown it provided with longitudinal extending ribs 24, 24, on the collarextending slightly above the transverse ribs 25, 25.

Preferably the combined thickness of the Wall of the anchor and the ribs is least at the outer end of the anchor, said combined thickness increasing to a maximum ata point intermediate the ends of the anchor, and then continuing at a substantially uniform combined thickness to the other end of the anchor.

In the different figures of the drawings, for.

purpose, of illustration, I have somewhat exaggerated the preferred angle of the inclined portion of the axial bore.

Having thus described this invention in connection with an illustrative embodiment thereof, to the details of which I do not desire to be limited, what is claimed as new and what Ais desired to secure by Letters Patent is set forth in the appended claims:

1. The combination of a hollow ductile an chor having a body portion which gradually increases in thickness from the outer end to a point intermediate its ends, and from that intermediate point being of substantially uniform thickness to substantially the other end of the anchor, and a screw adapted to cut its own coperating threads in the ductile anchor and to substantially expand the part having uniform thickness.

2. An article of manufacture comprising a ductile anchor having an internal inclined bore reaching yits minimum diameter between its ends and merging into a cylindrical bore, and internal ribs of substantially the same depth or height located on the inclined and cylindrical bores.

3. An article of manufacture comprising a ductile anchor having a body portion of varying thickness from one end to a point intermediate its ends and from that point being of uniform thickness to the other end of the anchor, said anchor being provided with an inclined and cyiindrical axial bore and `internal ribs mounted in the inclined and cylindrical axial bore.

HENRY W. PLEIS'IER. Witnesses:

MARY R. RYAN, A. M. Winfast/rs.

'lel 

